It has been common practice for many years to make paper, especially tissue, from recycled paper. Paper recycling has in recent years become an important and attractive alternative to disposal of wastepaper by deposition in landfills or by incineration. When the wastepaper source includes a significant amount of coated paper, as much as 30-45% of the original wastepaper will be reject material which is unusable for papermaking. This reject material has typically been discarded in landfills. Increasing costs and decreasing availability of landfill space makes it desirable to find beneficial uses for this reject material.
In the process of recycling waste paper, such as newspapers, magazines, office paper waste, the paper fibers are separated from the other solid components by using large quantities of water. The printing materials, such as laser print, photocopier print and ink, are removed before the paper fibers are conducted to the papermaking machine. Usually, these rejected solid materials are discharged with the water into large settling basins. The solid materials that settle out in the basins are then dumped in a landfill, or otherwise discarded. The material that settles out in the basins is known as paper mill sludge.
The increasing cost of wastepaper makes it desirable to capture as much of the papermaking fibers as practicable. In view of the large quantities of water required for papermaking, it is important to use a process that conserves water. There have been various proposals for systems for utilizing rejected solid materials such as paper mill sludge to produce absorbent granules and other products. Kaolin clay is one of the rejected solid materials that has been recognized as having good absorbent capabilities.
Conventional absorbent granules are produced from naturally occurring clay and are commonly used as agricultural chemical carriers. However, some of the agricultural chemicals (e.g., Diazinon) react with clay carriers. Accordingly, it would be advantageous to develop an agricultural chemical carrier that contains clay, but does not react with agricultural chemicals. Also, naturally occurring clays tend to create dust during handling. This is potentially hazardous to workers.